Dental hand piece



Nov. 25, 1941. u c msoN 2,263,808

" DENTAL HAND PIECE Filed May 2a, 1938 2 Sheets-Sheet 1 4 .zf/z/wza- 25 m 3 J70 M 2 I -36 4: 1 .1 %/Zc.r.r

NOV. 25,1941. HUTCHINSONY 2,263,808

DENTAL HAND PIECE Filed May 28, 1938 2 Sheets-Sheet 2 60 I 61 i Q 'scription proceeds.

Patented Nov. 25, 1941 UNITED .srmrss FATE-N T ossrcs DENTAL HANDPIECE Floyd M. Hutchinson, Tiskilwa, Ill.

Application May28, 1938, S'erialNo. 210:699

.. 7 Claims. (0153-2-47) This invention relates to theportion of a den- I taldrilling machine known as an'angle hand- .piece, and"particularlytothe structure of the head by which the :drill is removably carried. One object of the invention. is to, provide for the effective lubrication of .the lparts in a cleanly .manner so that the internal mechanism can be practically sealed against leakage of lubricant when in use, but readily opened for. the introductionof. fresh lubricant "when required. A further .object'of the invention is to arrange for the conv'enient manipulationofthe chuck by which the drills areremovably heldsof'that they maybe released or securedat'will without opening the "casing structure in which the moving parts are housed. Further. objects 'willappear'a's the de- The invention consists in the several features and elements of construction in combination, as herein shown and. described and as indicated by theclaims.

Inthe drawings:

Figure l is an axial section showing the head and elbow portions of the hand piece on a scale larger than the normal size of said parts, and

illustrating the application of forced "lubrication to the head for cleaning out the hand-piece.

Figure 2 is a section taken substantially at the common plane of the axes of the 'drill holding chuck and the "driving shaft. which is geared thereto.

head and chuck substantially at right angles to jtheiplane of Figure'2.

Figure 4 is'a transverse detail section taken at line l4 on Figure 2.

Figure 5 is a detail section taken at line"5- 5 on Figure 2.

Figure 6 is a detail elevation showing a'fraginentof the top of thecap"for the head.

'Figure'iis a sectionalvi'ew similar to Figure but showing a'modified construction.

Figure 8 is a sectional view taken' as indicated at line 'B-8 on Figure'l.

Figure 9 is a transverse section taken at line 9---9 on Figure 8.

Figure 10 'is a side elevation of the chuck "and its driving sleeve, with its adjusting nut shown Figure 3 is anaxial'section taken through the hollow spindle! may be similarly flared' at l5 'with'approximately the same taper, and this may be accomplished by swedging the end 'of' the through a flexible shaft connection, not shown. Adjoining the body "A is the benttubular' housing or elbow C, secured to the bodyA by-a threaded connection at C and enclosing apa'ir' of crown gears D and B through which the driveis trans proximately cylindrical portion land'a' second cylindrical portion 2 joinedjto the first at right angles. The end of the shaft -F carrying the gear G extends into the portion 2 beingdefinitely locatedtherein bytheengagement of the threaded end 3 of the neck E with the internally threaded bore" of thepart' 2. The end portion of the 'neck'E is formed with a grooved into which the extreme end of, the housing! telescopes; andto insure that" when the parts are thus screwed tightly together, the bent elbow portion C shall lie in exactly the correct relation to the head-I-I, a shim washer" 5 of the proper thickness maybe inserted in thegroove 4. Within the head "H, as may be best seen in Figure 2; the driving "gear G meshes withtheteeth of agear-G secured to the hollow spindle l. "The lower end of the housing I forms a journal hearing at 8 for the gear-6, and

the opposite end-of'the spindle! is formed with an oppositely tapered portion 9 for which a correspondingly shaped bearing l0 isfadjustably screwed into the upp'er'end of the shell I. Proper adjustment of the bearing 10' is maintained by a lock nut H screwed into the shell I. just above the bearing l0.

The hollowspindle'l carriesa clutch .sleeve l2 designed to'removably hold the drills, such as that shown at J in Figure 1. The sleeve I2 is longitudinally slotted as seen at l3, either three or four slots being provided torender the sleeve "compressible'in the lower portion of itslength,

and at the "extreme lower end said sleeve is formed withan outwardly flaring outer surface 14 of conical formation; the outer end of the spindle outwardly to occupy a slight counterbore in the end'of 'the driven gear-B for positioning the gear on the spindle, as seen in Figures 2 and 3.

At its upper end the clutch sleeve I2 is fitted with a rigidly secured head 16 externally threaded to receive a nut I1 and the latter rides normally on the upper end of the tapered journal portion 9 of the hollow spindle I. When the shank 20 of a drill J is inserted in the clutch sleeve I2, as shown in Figure 3, its upper end, if notched at 2|, may interlock with the projection 22 provided on the specially formed closure 23 at the upper end of the sleeve I 2; but the necessary frictional grip on the shank 20 for holding the drill firmly in place is supplied by contracting the clutch sleeve I2 about the shank. This is done by temporarily holding the nut I'I against rotation while allowing the spindle I to turn so that the threaded head I6 is forced upwardly toward the position shown in Figure 3, drawing with it the clutch sleeve I2 and forcing its flared end I4 into the hollow spindle I so that it may grip the shank 20.

As a convenient means for arresting the nut I1, or, at least, retarding its rotation in adjusting the clutch sleeve I2, I have shown a slide member 30 carried in the cap 25, which closes the upper end of the shell I, and I have shown the nut I I as of approximately square form (see Figure 4) but with its corners rounded as seen at IT, and with its upper edge beveled as at I l for engagement with the inclined stop surface 3i of the slide 30. The thumb-piece 32 of the slide 30 is accessible at the side of the cap toward the body A of the hand-piece so that the thumb of the hand which grasps the hand-piece may be readily caused to bear against the part 32, and shift the stop face 3I of the slider 30 into contact with the beveled surfaces I! of the nut II', thus tending to arrest the nut if it be rotating, or to hold it still so that the rotation of the threaded head IS in the nut I! may shift the clutch sleeve I2 axially. It will be evident that if said rotation is in one direction, the clutch will be tightened upon the shank 20, but if the direction of rotation is reversed, the clutch will be released by movement of the threaded head I6 back to its original position shown in Figure 2. To insure positive rotation of the clutch sleeve I2 it is provided with a drivinglug 2B projecting into a slot 21, which extends longitudinally through the tapered enlargement 9, which serves as a journal at the upper end of the spindle I.

If the nut I! were threaded clear through, the

rotation of the spindle in the direction for releasing the clutch sleeve [2 might tend to carry the threaded head I6 on the sleeve I2 beyond the lower face of the nut I'I, causing the latter to travel upward toward the cap 25;,however, as

shown in Figure 2, this is prevented by providing the nut with an annular lip I'I, extending inwardly at its lower end so as to limit the downward range of adjustment of the head I6 and prevent any tendency of the nut I l to travel upwardly on the threads of the head I6.

By reason of its inclined formation, the stop portion 3I of the slider acts to limit the upward travel of the threaded head I6 of the clutch sleeve I2, preventing the head I6 from being shifted so faras to become wedged against the under side of the cap 25. This might otherwise occur if the parts were operated without a drill in the sleeve. It is also possible that during operation of the drill, the endwise pressure upon the latter may tend to shift the sleeve I2 axially in the spindle I, wedging the flared end portions I4 a little more tightly, and carrying the nut I! out of contact with the journal portion 9 of the spindle; in this case the inclined relation of the shoulder 3| will cause it to exert an initial pressure axially of the sleeve I2 to effect an initial release of the tapered portions I 4 from the end of the spindle at I5.

The slider 30 is formed with flaring edges 33 so that it fits an under-cut groove in the cap 25. The thumb-piece 32 of the slider normally fits into a notch in the side wall of the cap 25 and the abutment or stop surface 3| is shown extending approximately at an angle of 45 degrees connecting the under face of the slider with the thumb-piece portion. This requires the cap 25 to be slotted to accommodate the inclined stop portion 3|, but the under-cut groove in the top of the cap is closely fitted to the slider, as is the notch in the side of the cap which the thumbpiece 32 occupies, so that the cap remains substantially oil-tight, notwithstanding the mounting of the movable slider in it. The movement of the slider is limited by a lug 34 on a terminal block 35 which is attached by a screw 35 to the end of the slider after the latter has been inserted in the under-cut groove of the cap. The cap and its slider are thus retained in assembled relation.

The cap 25 being screwed onto the reduced upper end of the shell I is readily removed therefrom when desired, and may be thus removed for supplying the hollow head H With fresh lubricant when required. Preferably, a grease gun or similar device having a discharge tube or nozzle P with a threaded coupling Q as indicated in Fig. 1, will be screwed onto the reduced threaded portion I of the shell I for thus supplying lubricant; and on such occasions the fresh lubricant will be forced throughout the cavity of the head H. The bearing for the shaft F in the end portion of the neck E may be formed with a longitudinal groove 40 which assists in conveying lubricant from the housing I through the neck E and into the elbow section C. The threaded end of the elbow is also provided at 4| with a channel extending from the cavity of the elbow which houses the gears D and D to the end of this part which abuts the end of the body A. When fresh lubricant is introduced into the casing I under pressure, as by means of a grease gun, it tends to force out the old grease by way of the passage 40, thence through the neck E and cavity of the elbow C through the channel 4| If desired, the elbow C may be provided with a special vent normally closed by a screw plug, seen at 42, for releasing the old grease, but a simpler arrangement for this purpose is afforded by partially unscrewing the body A from the elbow C thus providing a temporary outlet at the end of the channel 4| through which the old grease may escape as it is forced along by the fresh grease; hence, when clean grease begins to emerge at this point it will be an indication that the old grease has been cleaned out, and that the tool is now ready for further use. Then, by again tightening the connection between the parts A and C, and replacing the cap 25, the hand-piece will be rendered leak-proof. At the same time, the internal adjustment of the chuck sleeve I2, by means of the nut I I and slider 39, may be accomplished without any risk of releasing the lubricant to the external surface of the handpiece.

Figures 7 to 11 illustrate a head construction for a hand-piece, in which certain of the details are slightly "modified as ?compared *with those already described. In this formthehead itself is not materiallyjchanged, and includes the cylindrical port'ions I andtarranged for connection to 'thefineck section .E. "The "spindle 50 "carries-a gear 5! whichbears lathe, tapered-lower endof the casing l at 52, and-a secorid'bear-ing-forthe spindle'is shown at--53, screwedinto the casing and --engaging thetapered journal portion l 54.

"The bearing 53 is held at --ad;iuste'd position: Joya lock-nut" 55. l v,

For removably holdingilthe::drillsirin,thesspinidle. :56; a icl'utchrsleeve z5fijstcarried in the spindle and 11's iprovided with *outwardly bent ilugs 51 whichiengage longitudinal ,slotsj 56 and. 59 imthe upper :BlldnPOItiOfl-Of thespindle abovethe jourtnal =;portion 54. mile lugs-Jlproject through the slots s58. and i59 intolan annular groove 60*, in an adjustingnut 60 which .is. screwed .onto .the

,threaded upper endi6l of the spindle 50. -The .bore .of thespiridle5l] which.,accommodates the .clutch. sleeve 156; includes a tapered shoulder 62, and the clutch s1eeve56 is formed with 'a corresponding .taperedportion 63. The sleeveis formed with slots 64, opening through the lower end of the sleeve, and slots 64 which extend to its upper end, so that when shifted axially in the spindle 50 the entire length of the sleeve 56 will expand and contract under control of the tapered surfaces 62 and 63 to release or grip the shank of a drill. Such shifting of the clutch sleeve 56 is accomplished by movement of the nut 60 up or down upon the threaded portion 6| of the spindle.

As shown in Figure 9, the nut 60 has flat side surfaces 65 which may be engaged by the flat face 61 of a slider 66. The slider 66 is set in the cap 68 of the cylinder l and is similar to the slider 30 already described, except that the face 61 which is engageable with the flat faces 65 of the nut 60 extends parallel to the axis of the spindle 50 instead of obliquely thereto. When the slider face 61 is pressed into contact with one of the flat faces 65 of the nut 60, while the spindle 50 is rotated, the clutch sleeve 56 will be shifted up or down, depending on the direction of rotation of the spindle. The slider is fitted into the cap in leak-proof fashion; and the cap 68 may be unscrewed from the cylindrical shell I for the introduction of lubricant when required.

It will be recognized that in either form of the device there is no necessity of a spring for returning the slider 30 or 66 to its normal position, out of contact with the flat-sided, clutch-adjusting nut, since the rotation of the nut itself will tend to shift the slider to a position tangent to its rounded corners, where it will not interfere with the normal operation of the drill. And a slight pressure on the thumb-piece 32 of the slider 30 or the corresponding part 69 of the slider 66 will retard or arrest the adjusting nut and operate the clutch when desired.

It will also be evident that a positive driving engagement between the spindle and the clutch sleeve is not essential. In the form of the device shown in Figures 2 to 5 the omission of the lug 26 would leave the clutch tube frictionally engaged with the hollow spindle, but adapted to slip in the event of excessive load on the drill, which would frequently be an advantage.

In most hand-pieces the head portion in which the spindle and its drill are carried is of such dimensions as to more or less obstruct the dentists view of the point at which the drill is work- 111g? {Tm minimize this-difficulty thecontour of the head; I of the present desig-n -is tapered so that it narrows towards the point ofthedrill and permits of *a "reasonably good view of the work in progress.

- *While there isshown and described herein certain specific'structure embodying the invention, 'it will be-manifest to those skilled in the art"-that'various modifications and rearrange- "mentsof the parts may be made without departing fromthe Spirit'andscope of the invention, fan'd thatithesame is not limited to' the particular form hereinshown: and described, except in so far as indicated an the appended claims.

l."In"a dental hand-piece which includes a hollow spindlefa. head in which it is journaled and enclosed, a threaded. cap for said head re- 'mova'ble [for the "introduction of lubricant, a tubular clut'ch' member in the spindle, said spin- :dle'an'd clutc'htubehaving portions of their contacting surfaces" inclined to their common axis, whereby longitudinal adjustment of the'tube in "the 'spindletends to contract or expand the tube, a threaded partconnected to the clutch" tube for longitudinal movement therewith, a nut engaging said threaded part and a member slidably fitted in said cap having a portion engageable with said nut to resist rotation of the nut only and effect the longitudinal adjustment of the clutch tube while the spindle is rotating.

2. In a dental hand-piece which includes a hollow spindle, a head in which it is journaled and a split clutch tube in the spindle, said spindle and clutch tube having portions of their contacting surfaces inclined to their common axis, whereby longitudinal adjustment of the tube in the spindle tends to contract or expand the tube, a threaded part connected to the clutch tube for longitudinal movement therewith, a nut engaging said threaded part and formed with flat, laterally exposed faces, a member movably fitted in the head having a flat portion engageable with said lateral faces for arresting the nut alone while the spindle revolves, said member having an externally exposed portion positioned for operation by the thumb of the hand which holds the hand-piece.

3. In a dental hand-piece which includes a hollow spindle, a head in which it is journaled and a clutch member in the spindle arranged to be contracted or expanded by longitudinal adjustment therein, a threaded part connected to the clutch member for longitudinal movement therewith, a nut engaging said threaded part and means accessible outside the head and shiftable into arresting relation with the nut alone,

said means including a portion for holding the nut against longitudinal movement to insure longitudinal adjustment of "said threaded part and the connected clutch member while the spindle is rotating.

4. In a dental hand-piece, in combination, a hollow spindle, a clutch tube in the spindle and rotatable therewith, and a threaded nut, together with threaded means on one of the other two parts engaged with the threads of the nut, a head in which the nut is enclosed, and shiftable means guided in the head having an externally accessible portion and a portion inside the head engageable with the nut for holding only the nut against rotation while the spindle and clutch tube rotate, whereby the clutch tube is shifted longitudinally in the spindle.

5. In a dental hand-piece which includes a hollow spindle, a head in which it is journaled and enclosed, a tubular clutch member in the spindle expansible or contractible by longitudinal adjustment therein, said spindle having a longitudinal slot and the clutch tube having a lug extending through said slot for positive driving engagement with the spindle, the slotted portion of the spindle being externally threaded, a traveler nut on said threaded portion having an inwardly open annular groove into which said lug projects, whereby adjustment of the nut on the spindle shifts the clutch therein, and means accessible outside the head and shiftable into arresting relation with the nut to effect adjustment of the clutch while the spindle is rotating.

6. In adental hand-piece which includes a hollow spindle and a tubular clutch member in the spindle engaged for rotation therewith but longitudinally adjustable therein, a nut having threaded engagement with one of said members 1 and having a transaxial shoulder engaged with therother member, a head in which one end of said spindle and one end of said clutch member, together with said nut, are enclosed, a cap for said head normally fixed thereon during operation ofthe hand-piece, the means for holding said nut against rotation comprising a member slidably fitted in said cap with a portion inside the cap engageable with said nut and having a portion externally accessible on the cap positioned for operation by the thumb of the hand which holds the hand-piece.

7. In a dental hand-piece which includes a hollow spindle member and a tubular clutch member in the spindle engaged for rotation therewith but longitudinally adjustable therein, a nut having threaded engagement with one of said members and having a, transaxial shoulder engaged with the other member, a head in which one end of said spindle and one end of said clutch member, together with said nut, are enclosed, and shiftable means guided in the head having an externally accessible portion and a portion inside the head engageable with the nut for holding only the nut against rotation while the spindle and clutch member rotate, whereby the clutch may be adjusted longitudinally in the spindle; V

FLOYD M. HUTCHINSON; 

